diff --git a/Makefile.windows b/Makefile.windows
index 1ddcd3f..e397732 100644
--- a/Makefile.windows
+++ b/Makefile.windows
@@ -117,7 +117,7 @@ check-tools:
 	  echo "  Debian:  sudo apt install mingw-w64"; \
 	  echo "  Fedora:  sudo dnf install mingw64-gcc"; \
 	  echo ""; exit 1; }
-	@echo '#include <windows.h>' | $(CC) -x c - -fsyntax-only 2>/dev/null || { \
+	@echo '#include <windows.h>' | $(CC) -x c - -fsyntax-only -Wno-pragma-once-outside-header 2>/dev/null || { \
 	  echo ""; \
 	  echo "ОШИБКА: Windows API заголовки не найдены."; \
 	  echo "Установите пакет с заголовками MinGW-w64:"; \
diff --git a/comm.h b/comm.h
index 430f2c7..f0192f8 100644
--- a/comm.h
+++ b/comm.h
@@ -33,7 +33,7 @@ warren@wpratt.com
 #endif
 
 #ifdef _WIN32
-#include <Windows.h>
+#include <windows.h>
 #include <process.h>
 #include <intrin.h>
 #endif